Refillable cartridge-fuse.



I 0. H. JUNG REFILLABLE CARTRIDGE FUSE Armcn'mn' mz'u mm. my

1,246, 105; Patented Nov. 13,1917.

UNITED STATES PATENT oEEioE.

OSCAR H. JUNG, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ARROW FUSE & MFG. CO.,

OF MILWAUKEE, WISCONSIN.

REFILLABLE CARTRIDGE-FUSE.

Specification of Letters Patent.

Patented Nov. 13, 1917.

To all whom it may concern:

Be it known that I, Oscar. H. June, a citizen of the United States, and resident of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Refillable Cartridge-Fuses; and I do hereby declare that the following is a full, clear, and exact description thereof.

' This invention relates to new and useful improvements in cartridge fuses of that type which are adapted to be re-filled by the user thereof when the fusible strip is blown The primary object of the invention is to produce an inexpensive and simply constructed re-fillable fuse in which the fusible strip is inclosed, and one which will meet the strict requirements exacted of all approved fuses by the Underwriters Laboratories. v

Up to the present time the Underwriters Laboratories have steadfastly refused to an prove of any re-fillable cartridge fuse because of the much greater fire hazard compared to the ordinary non-re-fillable approved fuses. One of the chief disadvantages of any re-fillable fuse, lies in the fact that the fusible strip or link is inclosed merely in a non-conducting fiber casing, it not being surrounded by any arc-choking material. The makers of such rc-fillable fuses realize that a person who refills the fuse would not bother inclosing the links in such material, therefore only the links themselves are supplied with the casing which is to contain them. The result of having an uninclosed link is that a very destructive arc is created through the metal vapor whenever the fuse blows. Furthermore the continuance of the are is increased instead of diminished by the fiber casing. In other words, a strip of fusible material without any inclosure whatsoever would be preferable to a link incased in a fiber tube having its ends tightly closed.

Another object of inclosing the link in an arc-choking material is to reduce the induc tive kick which occurs whenever the fuse -blows. It is well known that when this kick occurs, it is frequently so violent as to burst ormaterially weaken the fibercasing if there is no arc-choking material contained therein. Theiheat also generated whenthe fuse is blown will quickly char the casing so that after the fuse has been re-filled a number of times the fire hazard will be very largely increased, inasmuch as the casing is liable to take fire at any time. Even though the fuse is not blown there is more or less heat created by the passage of current through the fusible strip, and if the latter is not inclosed, the fiber casing will quickly deteriorate, as it is a well known fact that heat or dryness will rapidly cause the layers of which the fiber is made to separate.

Another common disadvantage of such fuse, and one of the principal reasons why none have been approved by the Underwriters Laboratories is the ease with which it may be over fused. Over fusing is made simple by the construction of the ordinary re-fillable cartridge fuses by readily permitting more than one link to be inserted. The construction is also such that the terminals may even be bridged by copper wire or material other than fusible links. This also greatly increases the fire hazard, the user being tempted to oyer fuse to prevent frequent re-fillin g.

The present invention has been designed with the express purpose of. overcoming these and other heretofore necessary evils of the refillable cartridge fuse, and also one which will be more inexpensive than the ordinary type of n'on-re-fillable incloscd fuse. The de vice resides in the novel features of construction, combination and arrangement of parts which will be hereinafter more particularly described and claimed and shown in the drawings, wherein Figure 1 represents a side elevation partly in section of a fuse constructed in accordance with the invention.

Fig. 2 is a central longitudinal section or the self contained fuse member which is to be disposed in the fiber or other non-conducting casing.

Fig. 3 is an end view partly in section of the fuse member shown in Fig. 2.

Fig. 4 is a side elevation on a reduced scale ofthe complete fuse.

Referring more particularly to the several figures of the drawing wherein similar reference characters designate like parts, the

numeral 1 denotes a cylindrical tube of fiber;

or other non-conducting material having end members 2 in the form of ferrules the latter being preferably formed of copper and adapted to be inserted between the spaced contact points of a switch board or the like. In the present case the ferrules are adapted to be readily removed from the fiber casing 1 at the will of the operator to permit a self contained fuse member 3 to be disposed therein. The cylindrical walls of the ferrules at their inner edges are each provided with a bayonet slot 1, the same being adapted to en age screws or other headed elements 5 carried by the casing 1 adjacent the ends thereof. The ends 6 of the ferrules are counter-sunk as clearly shown in Fig. 1 for a purpose to be hereinafter set forth.

This casing including its end members may be of any appropriate size depending upon the amount of current which is to pass through the fusible strip connected between said end members. As herein before set forth the object of the invention is to produce a fuse which may be re-filled an innumerable number of times, therefore this casing is adapted to receive one of the fuse members 3, the same being changed for a similar member whenever it blows out.

The fuse member 3 comprises a cylindrical tubular shell 7 of any material such as stiff paper and is of such length that its ends will be in close proximity to the ends of end members of the casing when it is disposed therein. The shell 7 contains the fusible link 8 which is surrounded by a finely divided arc choking material 10, which is ordinarily formed largely of powdered plaster of Paris, for the usual purpose. The link is held in position against longitudinal shifting and the arc choking material is retained in the shell by the plugs 9, one of which is disposed in each end there of. The ends of the link 8 are extended beyond the ends of the shell and have eyes 11 formed thereon for attachment to the ends of the ferrules 2.

In Figs. 1 and 2 it will be noted that the plugs 9 are spaced inwardly from the ends of the shell a sufficient distance to permit thin poly-sided nuts 12 to be placed therein as most clearly shown in Fig. 3. One side of each nut will contact with the link 8 and thus their rotation. will be prevented and the threaded links of the bolts 13 engage therewith without danger of the former turning in said shell. One of these bolts is provided for each end of the casing, and the shanks thereof extend through central openings let in the counter-sunk portions 6 of the ferrules, the inner ends of said shanks being threadedly engaged with the nuts 12 when the fuse member 3 is placed in position Within the casing.

Before, however, the fuse member is inserted in the casing, the outwardly extending ends of the link 8 on which the eyes 11 are formed are bent laterally over the ends of the shell so that the openings in said eyes will aline with the openings in the nuts. By this arrangement the shanks of the bolts 13 will extend through the openings in the eyes 11 and thereby clamp said eyes between the nuts 12 and the ends of the end members or ferrules 2 when the same are tightened. A very tight and positive contact is thus formed which will prevent sparking and will be as effective as if the ends of the fusible links were soldered to the metallic end members of the casing. On the other hand the fuse may be readily removed from the casing when it blows out and anew one inserted. By counter-sinking the ends of the ferrules 2 as shown at 6, the heads of the bolts 13 will be so disposed that they will not engage any objects while the fuse is being inserted on the switch board or at any other time, inasmuch as they will be practically hidden as shown in Fig. 1.

It will be obvious to those skilled in the art that this combination of parts will overcome any and all objections which have been heretofore advanced against the use of refillable cartridge fuses. In the first place the fusible strip is inclosed in an arc choking material, and the shell which contains it is spaced from the inner wall of the easing 1 to thereby form an air chamber 15. The arc-choking material and the air in the chamber 15 will absorb the excessive amount of heat generated within the shell 7 so that the fiber casing will not be charred or injured in any way by the continued blowing of innumerable fusible links.

It will also be seen that it will be impossible for negligent users of the fuse to insert more than one link at a time, since the shell 7 is of suflicient size to occupy most of the space within the casing. Other and minor disadvantages of the usual re-fillable fuse have also been overcome in the present invention.

In supplying this improved fuse to the trade, one of the casings 1 and one of the fuse members will be provided. Each casing will include a fiber jacket with the detachable metallic end members, two nuts 12 and two bolts 13, all of these parts being usable many times, it being only necessary to place the nuts 12 in the ends of the fuse member and bending the eyes 11 thereover to make said fuse member ready for use. After it has blown the nuts 12 may be re moved and placed in a new member.

Various minor changes may be made in the different parts of the invention to accommodate them for use in fuses of differend sizes or design and with very little change over the structure illustrated, the fuse member 3 may be used in connection with the casings of any type of refillable fuse, such as the Economy fuse now on the market.

I claim:

1. An electrical connection comprising, in combination, a non-conducting casing having end members, a self contained fuse mem ber removably disposed in said casing and including a shell, a fusible strip disposed therein, the ends of the strip extending beyond the ends of the shell and having eyes formed thereon, a nut in each end of the shell, and a bolt extending from each end member and connected with the nuts, the shanks of said bolts extending through said eyes, the latter being clamped between said nuts and the end members.

2. An electrical connection comprising, in combination, a non-conducting casing having end members, the ends of said end memmers being counter-sunk, a self contained fuse member removably disposed in said casing and including a shell, a fusible strip disposed therein, the ends of the strip extending beyond the endsof the shell and having eyes formed thereon, a nut in each end of the shell, and a bolt extending from each end member and connected with the nuts, the shanks of said bolts extending through said eyes, the latter being clamped between said. nuts and the end members, the heads of said bolts being disposed in said counter-sunk portions of the end members.

3. An electrical connection comprising, in combination, a non-conducting casing having end members,aself containedfuse member removably disposed in said casing and including a shell, a fusible strip disposed therein, the ends of the strip extending beyond the ends of the shell, a nut in each end of the shell, and a threaded connection between each end member and the adjacent nut, the ends of the fusible strip being clamped between said nuts and the adjacent end members.

4. An electrical connection comprising, in combination, a non conducting casing having end members, a selfcontained fuse member removably disposed in said casing and including a shell, a fusible strip disposed therein, the ends of the strip extending beyond the ends of the shell, plugs in the ends of the shell for closing the same, said plugs being spaced inwardly of the ends, nuts in the ends of the shell and seated on said plugs, and a threaded connection between each end member and the adjacent nut, the ends of the fusible strip beingclamped between said nuts and the adjacent end members.

5. An electrical connection comprising, in combination, a non-conducting casing having end members, a self contained fuse member removably disposed in said casing and including a shell, a fusible strip disposed therein, the ends of the strip extending beyond the ends of the shell and having eyes formed thereon, an arcchoki.ng material disposed around said strip in the shell, plugs for closing the ends of the shell, said plugs being spaced from the ends of the shell, nuts in the ends of said shell, and a bolt extending from each end member and connected with the nuts, the shanks of said bolt extending through said eyes, the latter being clamped between said nuts and the end mem bers.

6. A self-contained fuse member to be used in the casing of refillable cartridge fuses comprising a shell, a fusible strip disposed in the shell, the ends of the strip extending beyond the ends of the shell to be attached to the ends of said refillable can tridge fuse casing, said ends lying adjacent the inner wall of the shell, plugs for closing the ends of the shell, said plugs being spaced inwardly from said ends, and poly-sided attaching members disposed in the ends of the shell and seated on said plugs, one of the flat faces of each of said members being engaged with the adjacent end portion of the fusible strip, whereby to prevent rotation of said members.

7. A self-contained fuse member to be used in the casing of refillable cartridge fuses comprising a shell, a fusible strip disposed in the shell, the ends of the strip extending beyond the ends of the shell to be attached to the ends of said refillable cartridge fuse casing, said ends lying adjacent the inner wall of the shell, plugs for closing the ends of the shell, said plugs being spaced inwardly from said ends, and attaching members disposed in the ends of the shell and seated on said plugs, the extended ends of said fusible strip being bent laterally and over said members.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee and State of isconsin.

OSCAR II. JUNG.

Copies of this patent may be obtained for five cents each, by addressing the Gommissioner of Patents, Washington, I). C. 

